It said Oxfam's country director for Haiti, Roland van Hauwermeiren, used prostitutes at a villa rented for him by Oxfam in the aftermath of the 2010 earthquake.

According to the paper, Oxfam knew about concerns over the conduct of Mr van Hauwermeiren and another man when they worked in Chad before they were given senior roles in Haiti.

On Monday, the charity's deputy chief executive Penny Lawrence stepped down saying she was "ashamed" and takes full responsibility.

The letter to international charities funded by the Scottish government added: "We expect our partner organisations wherever they are to monitor their work closely, and to be open, honest and transparent with us, and the public whenever there are any suggestions of abuse or malpractice.

"Therefore, I am asking all international NGOs that the Scottish Government funds to confirm that you have robust safeguarding policies in place to protect vulnerable groups, and that if you have become aware of specific incidents, that they have been referred to the relevant authorities where necessary."

Scotland's international development minister said he recognised that the vast majority of those working in the sector "do so in a diligent and appropriate manner".

But Mr Allan added: "The Scottish government will not hesitate to take appropriate action whenever we suspect that any abuse has occurred, and we expect the same commitment from those working with us."